Musannaf Ibn Abi Shayba 13:2444

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Sufyan narrated to us, from ‘Abdullah bin Dhakwan Abu al-Zinad, from ‘Abd al-Rahman bin Hurmuz al-A’raj, from Abu Hurayrah, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "The procrastination of the wealthy is an injustice. And whoever is referred (for payment) to a solvent person, let him accept the referral."